Improvement in lifting-jacks



UNITED STATES PATENT FFICE.

JOHN SLONEKER AND WILLIAM J. MCMINN, O F JEFFERSON, PENNSYLVANIA, ASSIGNORS TO WILLIAM J. MCMINN, OF SAME PLACE.

IMPROVEMENTv IN LlFTlNG-JACKS.

Specification forming part of Letters Patent No. 155,764, dated October 6, 1874; application filed v September 7, 1874.

To all whom it may concern: l

Be it known that we, JOHN SLONEKER and WILLIAM J. MOMINN, of Jefferson, in the county of Greene and State of Pennsylvania, have invented a new and useful Improvement in L'fting-Jacks 5 and we hereby declare the following to be a full, clear, Vand exact description of the same, reference being had to the accompanying drawing, making a part of this specification, in which- Figure l is a side elevation, and Fig. 2 is a vertical sectional view, of a lifting-jack embodying our improvements. Fig. 3 is a perspective view of the shaft I and rollers J J.

This invention relates to an improvement in lifting-jacks; and it consists of a lifter-bar working in grooves, and having a ratchet in one edge and a notched slot traversing it laterally, the latter being provided with a shaft having a roller on each end, in combination with a detent and lever provided with a springlever, connected with the detent for Withdrawing the same from the ratchet at will; the object being to produce an improved lifting-jack, the operation of which will hereinafter fully appear.

In the accompanying drawing, the uprights A and B areprovided with grooves C, which receive the edges of the lifter-bar D, and in which the latter Works. The lower ends of the uprights A and B are mortised intoa baseplate, E, and the upper ends of the same are bound by a metallic girdle, F.' A roller, S, in the upright A lessens the friction when the bar D is being raised. The lifter-bar D is provided with the ratchet G in one edge, and, near its center, with the notched slot H, which traverses it laterally. A shaft, I, provided with a roller, J, at each end, occupies the notched slot H, the rollers J J projecting on each side of the slot H.. A detent, K, occupies a slot, L, in the upright B, and is so halanced as to engage with the teeth of the ratchet G by the force of its own weight. A spring-lever composed of the lever M, rod N, spring O, and chain I), secured in the main lever Q, connects with the detent K, and is used for withdrawing the detent from the ratchet Gr when it is desired to lower the lifter- .bar D. Thelever Q is bifurcated and secured to the upright B, one fork on each side of the uprights A and B. The upper sides of the forks of the lever Q curve downwardly toward its point, and the curves are faced with metal strips B. It, upon which the rollers J J travel when the device is being operated. Any number of notches may be made in the slot H, and said slot may be lengthened, if desired. y

When the device is in its first position, or at rest, the power end of the lever Q is elevated, the lower end ofthe liftenbar D is just above the top of the base-plate E, the shaft I in the top notch of the slot H, the rollers J J resting upon the strips R R of the lever Q, and the detent K resting in the top notch of the ratchet Gr. To elevate the lifterbar D, depress the power end of the lever Q. If a full depression of the lever Q should not raise the lifter-bar D to the required height, elevate the power end of the lever Q un'til the shaft I drops from the upper to the second notch in the slot H, and again depress the power end of the lever Q. If neccessary, the third and fourth notches may be gained in the saine manner. When it becomes necessary to lower the lifter-bar D, depress the power end of the lever Q until the weight ot' the lifter-bar is removed from the detent K, and press inwardly on the power end of the lever M, which operation withdraws the detent K,` and permits the `lifter-bar to be gradually lowered by gradually elevating the power end of the lever Q. Having thus described our invention, what we claimas new and useful, and desire to secure by Letters Patent, is-

In a lifting-jack, the lifter-bar D, working in grooves C, and having the ratchet G and notched slot H, the latter provided with the shaft I, having the rollers J J on its ends, in

combination with the detent K and lever Q, provided with the spring-lever M N O P, substantially as set forth.

In testimony that we claim the foregoing improvements, as above described, we have hereunto set our hands andseals this 31st day of August, 1874.

JOHN SLONEKER. WILLIAM J. MGMIN N Witnesses:

DANIEL ANsLEY, IsAAc H. SMITH. 

